Title :
NbN/MgO/NbN SIS tunnel junctions for submm wave mixers
Author :
Stern, J.A. ; Hunt, B.D. ; LeDuc, H.G. ; Judas, A. ; McGrath, W.R. ; Cypher, S.R. ; Khanna, S.K.
Author_Institution :
Jet Propulsion Lab., Pasadena, CA, USA
fDate :
3/1/1989 12:00:00 AM
Abstract :
The authors report on the fabrication and testing of all-refractory NbN/MgO/NbN SIS (superconductor-insulator-superconductor) tunnel junctions for use as high-frequency mixers. Progress in the development of techniques for the fabrication of submicron-area tunnel junctions is described. Junction structures which have been investigated include mesa, crossline, and edge geometries. Using reactive sputtering techniques, NbN tunnel junctions with critical currents in excess of 10 4 A/cm2 have been fabricated with Vm values as high as 65 mV and areas down to 0.1 μm2. Specific capacitance measurements on NbN/MgO/NbN mesa-type tunnel junctions give values in the range 60-90 fF/μm2. These SIS tunnel junctions have been integrated with antennas and coupling structures for mixer tests in a waveguide receiver at 207 GHz. Preliminary mixer results are reported
Keywords :
critical currents; magnesium compounds; mixers (circuits); niobium compounds; solid-state microwave devices; sputter deposition; submillimetre wave devices; superconducting junction devices; type II superconductors; 207 GHz; 65 mV; EHF; NbN-MgO-NbN; SIS tunnel junctions; THF; antennas; coupling structures; critical currents; crossline geometry; edge geometries; fabrication; mesa-type; microwave device; reactive sputtering; specific capacitance measurements; submicron-area tunnel junctions; submillimetre wave devices; submm wave mixers; superconductor-insulator-superconductor; testing; waveguide receiver; Capacitance measurement; Critical current; Fabrication; Geometry; Josephson junctions; Receiving antennas; Sputtering; Superconducting devices; Testing; Waveguide junctions;
Journal_Title :
Magnetics, IEEE Transactions on
